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loop: raise media_change event 

Make the loop device raise a DISK_MEDIA_CHANGE event on attach or detach.

	# udevadm monitor -up |grep -e DISK_MEDIA_CHANGE -e DEVNAME &

	# losetup -f zero
	[    7.454235] loop0: detected capacity change from 0 to 16384
	DISK_MEDIA_CHANGE=1
	DEVNAME=/dev/loop0
	DEVNAME=/dev/loop0
	DEVNAME=/dev/loop0

	# losetup -f zero
	[   10.205245] loop1: detected capacity change from 0 to 16384
	DISK_MEDIA_CHANGE=1
	DEVNAME=/dev/loop1
	DEVNAME=/dev/loop1
	DEVNAME=/dev/loop1

	# losetup -f zero2
	[   13.532368] loop2: detected capacity change from 0 to 40960
	DISK_MEDIA_CHANGE=1
	DEVNAME=/dev/loop2
	DEVNAME=/dev/loop2

	# losetup -D
	DEVNAME=/dev/loop1
	DISK_MEDIA_CHANGE=1
	DEVNAME=/dev/loop1
	DEVNAME=/dev/loop2
	DISK_MEDIA_CHANGE=1
	DEVNAME=/dev/loop2
	DEVNAME=/dev/loop0
	DISK_MEDIA_CHANGE=1
	DEVNAME=/dev/loop0

Signed-off-by: Matteo Croce <mcroce@microsoft.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Luca Boccassi <bluca@debian.org>
Link: https://lore.kernel.org/r/20210712230530.29323-7-mcroce@linux.microsoft.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Matteo Croce 2021-07-13 01:05:30 +02:00 committed by Jens Axboe
parent e6138dc12d
commit 9f65c489b6
1 changed files with 5 additions and 0 deletions
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5
drivers/block/loop.c
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@ -774,6 +774,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
goto out_err;
/* and ... switch */
disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE);
blk_mq_freeze_queue(lo->lo_queue);
mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
lo->lo_backing_file = file;
@ -1257,6 +1258,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
goto out_unlock;
}
disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE);
set_disk_ro(lo->lo_disk, (lo->lo_flags & LO_FLAGS_READ_ONLY) != 0);
INIT_WORK(&lo->rootcg_work, loop_rootcg_workfn);
@ -1410,6 +1412,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
partscan = lo->lo_flags & LO_FLAGS_PARTSCAN && bdev;
lo_number = lo->lo_number;
disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE);
out_unlock:
mutex_unlock(&lo->lo_mutex);
if (partscan) {
@ -2386,6 +2389,8 @@ static int loop_add(int i)
disk->fops = &lo_fops;
disk->private_data = lo;
disk->queue = lo->lo_queue;
disk->events = DISK_EVENT_MEDIA_CHANGE;
disk->event_flags = DISK_EVENT_FLAG_UEVENT;
sprintf(disk->disk_name, "loop%d", i);
add_disk(disk);
mutex_unlock(&loop_ctl_mutex);